Acute Flaccid Myelitis (AFM): What it is and what to know about it

(RNN) – Acute flaccid myelitis (AFM) has caused concern around the country this year as the number of cases of the disease, which impairs motor functions and has been compared to polio, has seen an unexplained spike.

The Centers for Disease Control and Prevention (CDC) announced last month that it was investigating the recent spate of cases.

The agency has said it is “concerned” about the disease, which has had 404 confirmed cases across the U.S. since August 2014, mostly in children.

Here are some things to know about the illness:

According to the CDC, it affects “specifically the spinal cord, which can cause the muscles and reflexes in the body not to work normally.”

Its exact cause is not known, though the CDC says it could be linked to other viruses or environmental toxins.

So far this year, there have been 80 confirmed cases, and 219 total patients under investigation for the disease.

The spike in confirmed cases comes after there were just 33 in 2017. However, the recent increase hasn’t yet reached the levels of 2016 (when there were 149 confirmed cases) or 2014 (when 120 cases were confirmed just between August and December).

For reasons that are not yet understood, cases usually spike between August and December and then taper off through the rest of the year.

Significant spikes in AFM were seen this year, in 2016 and in 2014. (Centers for Disease Control and Prevention)

Symptoms can include: weakness and loss of muscle tone and reflexes in the arms or legs, facial droop or weakness, difficulty moving the eyes, drooping eyelids, difficulty swallowing and slurred speech.

While scary, the CDC stresses that it still “remains a very rare condition.” It affects fewer than one in a million people.

According to the agency, “there is no specific treatment for AFM.” Some doctors who specialize in neurological disorders may recommend “physical or occupational therapy to help with arm or leg weakness caused by AFM.”

There is no officially known long-term outlook or expected outcome for AFM patients.

However, a 2017 National Institutes of Health study that tracked eight children with the disease in Colorado saw six continue to have “persistent motor defects” one year after contracting the illness and just two make a full recovery. Of another four children who did not participate in the study, two reported a full recovery one year later.

The CDC advises: “While we don’t know the cause of most of the AFM cases, it’s always important to practice disease prevention steps, such as staying up-to-date on vaccines, washing your hands, and protecting yourself from mosquito bites.”